Phthalic acid esters



Patented July 25, 1939 t t PHTHALIC ACID Es'rEits John B. Tuttle, Elizabeth, N. 1., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application May 2, 1935, Serial No. 19,507

1 Claim. (Cl. 260-475) This invention relates to novel plasticizers and lar desired fraction, or after neutralization of methods of preparing same. These plasticizers organic acids with caustic soda. are intended particularly for use with pyroxylin, The finished product consists chiefly of a mixenamels and lacquers, although it is not intendture of aliphatic alcohols having more than 5 ed that the invention be limited specifically to carbon atoms, some having as high as 25 or 5 these particular uses. more, but usually averaging about 16 to 18 car- Broadly, the invention comprises preparing bon atoms. plasticizers by esterification of high molecular Many diifereut acids can be used for the esterweight alcohols obtained by the oxidation of subiflcation, the following being typical examples:

l0 stantially solid petroleum hydrocarbons, espel0 cially paraffin wax. Type Name Formula In order to prepare the high molecular weight alcohols, a suitable starting material such as Inorganic Boric mp0,, paraflin wax, petrolatum or other mineral hydro- Egg-322g? g=gg carbon of a waxy nature, is oxidized at 140 to o i I 2 1 200 C. with a small amount of oxidation cataeJipham-mmbasihm gf igif 8Pfg lyst by blowing with air for a period ranging Stearic cnuhcoon. from one-half to six hours or so, depending upon ggigggggg the reaction conditions, the longer time being I dibasic(sat.) sue ihiefj 0211400011. 20 required at the lower temperature. Various c atifi f g gzggggggf gg gfl 20 alysts, such as manganese soaps of fatty acids, Adipicu O,H(000H). may be used, particularly the higher fatty acids gggzgggggg: and the manganese soaps of acids produced by e tribasic .l Citric oindonxooonfl the oxidation of paraffin wax. Other oxidation Ammam i gifgf g ifi ggggcatalysts include oxides, soaps, or other com- 25 pounds of other heavy metals, such as lead, cobalt, etc.

'Although it is possible to use tion products directly as the material to be esterified, it is preferable to separate any unoxidized wax from the oxygenated products by extraction with a suitable solvent or by any other suitable means, and it is still further preferable to subject this extract, which may contain from 30 to 60% or so of alcohols, as such or after the organic acids have been neutralized with caustic soda, to hydrogenation under conditions adapted alcohols produced as described above y be to cfmvert most of the.aldehydes k f and carried out by any suitable means, for instance, possibly some of the acids present into primary by heating to about to C- the high One may also use acids from oxidized wax, acids from oxidized oils, rosin, turpentine, etc., as the crude oxida well as acids such as condensation products of maleic acid and diolefins. 30

It is of course understood that the above acids are only given'for the sake of illustration and the invention is not intended to be limited thereto. It should be pointed out, however, that the dibasic aliphatic and aromatic acids are partic- 35 ularly suitable for carrying out the invention.

The esterification of the high molecular weight 40 d Secondarti alcohols Espectwely wlthout molecular weight alcohols and the desired acid 40 'causing appreclable converslon of alcohols (or mixture of acids) in approximately molar already Present to hyqrocarbonshydro proportions so as to obtain approximately a neugena may be earned put, for Instance at tral product. Suitable esterification promoters 150 to 2 a Pressure of 50 to 300 or catalysts may be used such as a small amount 45 mospheres, with a suitable hydrogenation cataof Sulfuric acid or dry hydrogen chloride gas, lyst suc as nickel, for a length Of time ranging boron fluoride, etc. The finished ester may be between the appr a limits of one-half hour subjected to further refinement, if desired, by to five hours dependi upon the severity of the washing with water or with dilute solutions of ydr n oonditions- The resulting hydroacids or bases or clay treating, heat treating or genated product may be used as such or after by air b i still further efi S as y fractional Although these ester products may find varitillation or precipitation or extraction with sut-- ous ind st ial use depending upon h w they able solvents to remove impurities or to remove were prepared, yet they have been found par- 55 any undesired fraction or to obtain any particuticularly suitable for use as plasticizers for pyroxylin, enamels, lacquers, etc. including fllms such as regenerated cellulose and cellulose acetate (used extensively in safety glass). For such use, the crude or refined ester product may be used as such or after fractionation, by distillation (preferably in vacuo) precipitation, etc., to a particular boiling range, e. g. betweenthe approximate limits of 200 and 450 C. For these purposes a series of esters of a homologous series is much better'than a pure ester from the point oi view of evaporation, activity, action on film, blushing, etc. They also have the additional important advantage of lower cost compared to single pure compounds capable of use for similar In using the plasticizers prepared according to the present invention, the desired pyroxylin, lacquer, or other stock to be piasticized is compounded with a mixture of the plasticizer and a suitable solvent, such as solvents obtained by the oxidation or hydrogenation (solvesso) of liquid petroleum fractions, various esters of acetic acid, diethyl carbonate, benzoi, toluol, solvent naphtha, etc., with or without pigments or dyes, oxidation inhibitors, and other addition agents known to the art.

For the sake of illustration only and without intention of limiting the invention thereto, the folio wing specific example is given:

Refined paraflln wax is oxidized in the presence of 0.1% of soda ash at a temperature of 160 C. by air blowing for 4 hours (at 180 C. 2 hours would be sufllcient). 'The crude oxidation product is found to have the following approximate composition:

Per cent Unoxidized wax. Alcohols averaging 14 to 16 carbon atoms 40 Aidehydes and ketones 40 The extract is then hydrogenated at 180 C. under a pressure of 100 to 200 atmospheres, using a nickel-kleselguhr catalyst for 1 to 3 hours. The product is found to comprise about 80 to 95% of alcohols and 5 to 20% of carbonyl compounds (aldehydes and ketones). About 400 parts of this hydrogenated product consisting largely of high molecular weight aliphatic alcohols are then reacted with about 150 parts oi.

phthaiic anhydride at a temperature of about 150 C. until reaction is substantially complete.

The resultant ester product is neutralized and fractionated to a boiling range 01' about 250 to 300 C. One part of this plasticizer is then mixed with 3 parts of ethyl acetate and 1 part of pyroxylin. The amount of plasticizer to be used will vary, as is known to those skilled in the art, according to the intended use as well as the boiling point and viscosity of the plasticizer and the amount, kind, and proportions of the solvent and the coating material to be plasticized.

The invention is not to be limited to the specific embodiments shown nor the specific examples given, but in the appended claim it is intended to claim all inherent novelty in the invention as broadly as the prior art permits.

I claim:

Method 01' preparing'ester products adapted to be used as plasticizers for pyroxylin, enamels, lacquers and the like, which comprises oxidizing paraflln wax with air at about 140-200 C. for about to 6 hours in the presence of an oxidation catalyst, separating the oxidized products from the unoxidized hydrocarbons, subjecting the oxidized products to hydrogenation at about 150-200 C. and about 50-300 atmospheres for to 5 hours in the presence of a hydrogenation catalyst, esterifying the resulting product consisting largely of high molecular weight aliphatic alcohols with a dibssic acid selected from the group consisting of phthalic acid and anhydride and separating from the resulting esterified product a fraction having a boiling range of about 250-300" C.

JOHN B. TUTTIE. 

